我国胰腺炎最常见病因（）。

A.胆道疾病

B.过量饮酒

C.暴饮暴食

D.高脂血症

E.十二指肠液反流

The large size and roughly circular shape of the Pacific made some scientists think that it ()a hole left when the moon separated from the earth.

A. used to be

B. would have been

C. might have been

D. should have been